Folding blade cylinder of a folding machine

ABSTRACT

A folding blade cylinder for use in a folding machine includes a cylindrical cradle and a folding blade that can be situated in various positions in the cylindrical cradle. Each position of the folding blade corresponds to a gap in the cylinder cradle surface. These gaps are separated from ach other by segments of the cylindrical cradle. In order to move the folding blade from one gap to another, the folding blade is retracted into the interior of the folding blade cylinder.

FIELD OF THE INVENTION

The present invention is directed to a folding blade cylinder of afolding machine. The folding blade cylinder has a cylindrical cradle orsaddle and a folding blade which can be extended from an opening gap inthe cradle and which can be displaced circumferentially betweendifferent positions on the folding blade cylinder.

BACKGROUND OF THE INVENTION

Folding blade cylinders are employed, typically acting together with afolding jaw cylinder, for making a transverse fold in a sheet ofmaterial which is passing through a gap between the folding bladecylinder and the folding jaw cylinder. To accomplish this, at least onefolding blade in the folding blade cylinder can be moved between aninactive position, in which it does not protrude outwardly past theexterior surface of the folding blade cylinder, and an active positionin which the folding blade extends out past the folding blade surface.In the active position, the folding blade pushes the sheet to be foldedinto a gap in the oppositely located folding jaw cylinder, which gap issubsequently closed. The folding jaw cylinder then conveys the foldedsheet clamped in the fold further.

In order to be able to fold sheets in various formats by the use of sucha folding blade cylinder, or to form different folds, it is necessary tobe able to displace the folding blade on the circumference of thefolding blade cylinder between different positions. However, theexterior surface of the folding blade cylinder should be cylindricallyclosed to as great an extent as possible in order to assure the preciseguidance of the sheets of metal.

DE 43 35 048 A1 describes a folding blade cylinder for a foldingapparatus with a single gap for the folding blade. The folding blade canbe displaced inside this gap in the circumferential direction of thefolding blade cylinder.

DE 690 08 007 T2 shows a folding blade cylinder with a folding blade.The folding blade can be moved into a working and a rest position fordifferent types of folds.

DE 12 22 082 A discloses a folding blade cylinder of a cylinder foldingapparatus. The folding blades can be displaced, in the retractedposition, in the circumferential direction in the interior of thefolding blade cylinder.

SUMMARY OF THE INVENTION

The object of the present invention is directed to on providing afolding blade cylinder of a folding machine.

In accordance with the present invention, this object is attained by theprovision of a folding blade cylinder of a folding apparatus. Thefolding blade cylinder has a circumferential cradle and a folding bladewhich can be extended radially from a gap of the cradle. The foldingblade can be displaced circumferentially between different positions onthe folding blade cylinder. A plurality of gaps are provided in thecircumferential direction of the folding blade cylinder cradle. Thefolding blade can be selectively displaced so that it lies oppositedifferent ones of those plurality of gaps.

The advantages to be gained by the present invention lie, in particular,in that an impediment to the displacement of the blade cylinder by theaccumulation of paper dust or of similar foreign materials is madeimpossible, even after a long period of use of the folding bladecylinder with a particular format. Another advantage of the presentinvention consists in that the formation of tooth-shaped impressions inthe sheet to be folded are prevented.

To this end, in place of a single displaceable gap, the cradle has aplurality of gaps which are each assigned to a folding blade. Thefolding blade can be retracted into the interior of the folding bladecylinder sufficiently far so that the folding blade can be displaced inthe interior of the folding blade cylinder between different foldingblade positions, each of which folding blade positions being locatedopposite one of the gaps.

This can be accomplished for one reason because the lift of the foldingmovement can be selected to be so large that, in its inactive position,the folding blade is located radially inside the interior surface of thecradle. The folding blade can be freely displaced in this position.Another option is to provide a reduced lift of the folding movementbetween the extended active and the retracted inactive positions of thefolding blade. In the inactive position, the folding blade is at leastpartially located outside of the inner surface of the cradle. Thefolding blade can be embodied so that it can be retracted behind theinterior surface of the cradle in order to make possible thedisplacement of the folding blade to another cylinder or cradle gap.

Customarily, the radial movement of such a folding blade is controlledby a lever which runs against or on a control cam. In order to be ableto retract the folding blade past the usual inactive position, it ispossible to provide an actuator that is usable for lifting the lever offthis control cam. Such an actuator can be a lift cylinder, for example.Electro-magnetically driven actuators can also be considered. A secondcontrol cam can also be provided, which second control cam can bedisplaced against the first control cam and which second control cam hasa section which can be brought into contact with the lever arm by thisdisplacement in order to retract the folding blade into the interior ofthe folding blade cylinder and into a position behind the interiorsurface of the cradle.

To prevent the edges of the gap or gaps in the cradle of the foldingblade cylinder from pressing into the sheet to be folded, the exteriorlylocated longitudinal edges of the gaps can be beveled.

Furthermore, a closing body is preferably provided which closing body,coupled with the displacement of the folding blade, can be displacedbetween one position, in which it does not close a gap occupied by thefolding blade, and a second position wherein it is not retracted intothe interior of the folding blade cylinder. Such a closing body can alsocounteract the formation of an indentation, in particular if it restsflush with the exterior surface of the cradle on a portion of theexterior surface. However, the closing body is more important in that itprevents the introduction of a free end of a sheet into an otherwiseopen gap.

To ease the displacement of the closing body, and therefore also that ofthe folding blade, the closing body and/or the gap which can be closedoff by the closing body are beveled on their ends facing each other. Aspring element can be used for maintaining the closing body in itsposition by the use of a radially outwardly exerted spring pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention are represented in thedrawings and will be described in greater detail in what follows.

Shown are in:

FIG. 1, a schematic radial cross-section through a folding bladecylinder in accordance with the present invention, in

FIG. 2, an axial cross-section through the folding blade cylinder inFIG. 1, in

FIG. 3, a first modification of the folding blade in a radial partialcross-section, in

FIG. 4, a second modification of the folding blade in a radial partialcross-section analogous to the view shown in FIG. 3, and in

FIG. 5, a third modification of the folding blade in a radial partialcross-section analogous to the view shown in FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first preferred embodiment of the folding blade cylinder in accordancewith the present invention, and shown in a radial cross-section, and inan axial cross-section is represented in FIGS. 1 and 2, respectively.The axial cross-section shown in FIG. 2 shows a shaft 01, to which twoflanges 02 have been screwed, which flanges 02 are fixed againstrelative rotation with respect to shaft 01. These flanges 02 support acradle 03, as seen in FIG. 1, of the folding blade cylinder which cradle03, in this first preferred embodiment, has been put together from sixcradle segments 06, 07, which are respectively separated by gaps 08, or09, with these cradle segments 06, 07 and their associated gaps 08, 09extending radially over the entire distance of the folding bladecylinder between the flanges 02.

Three holding elements 12 that are each equipped with grippers extendthrough slits placed in the segments 06. These three holding elements 12are each mounted on respective spindles 11, which spindles 11 are, inturn, pivotably suspended between the two inboard flanges 02.

Two additional, outboard flanges 13 are arranged so as to be supportedby and rotatable around the shaft 01 and parallel with the flanges 02,as seen in FIG. 2. Cross arms 14 are secured to the outboard flanges 13and extend axially through elongated holes 16 each formed in the shapeof a segment of a circle in the flanges 02 and connect the flanges 13with each other for coupling the rotary movement of the flanges 13. Asrepresented in FIG. 1, in the area between the flanges 02 the cross arms14 are combined into a hollow cylinder surrounding the shaft 1 in orderto achieve the greatest possible torsional rigidity for the foldingblade cylinder.

Three spindles 17 of folding blades 18 are rotatably seated on theoutboard flanges 13, as seen in FIGS. 1 and 2. Each one of the grippers12 and the folding blades 18 performs a back-and-forth movement in timewith the rotation of the folding blade cylinder, which back-and-forthmovement is controlled in a generally known manner by levers 19, or 21,respectively that are mounted on axial ends of the spindles 11, or 17,respectively. These levers 19, 21 support rollers 22 on their ends,which rollers 22 each roll off on control cams 23, as seen in FIG. 3.These control cams 23 are in the form of stationary disks. They are notrepresented in FIG. 2, and in FIG. 1 are shown only in the form of partsof a surface, as shown by the discontinuous line 23 in FIG. 1.

In order to differentiate between the three folding blades 18represented in FIG. 1, in the discussion which follows these threefolding blades 18 will also be called the right, left, or lower foldingblades 18, all with reference to their respective locations in FIG. 1.The left and the lower folding blades 18 depicted in FIG. 1 are in aninactive position in their folding movement, in which inactive positionsthey have been retracted radially inwardly as far as possible topositions behind an inner surface 24 of the cradle 03. The right foldingblade 18 depicted in FIG. 1 is in an extended, active position, in whichits tip or outer end slightly protrudes past an outer surface of thecradle 03 and is therefore capable of pushing a sheet, which is carriedalong on the folding blade cylinder by the gripper 12, into a foldingjaw of an oppositely located folding jaw cylinder, which is notspecifically represented.

In a position of the folding blade cylinder, which is slightly displacedwith respect to the represented position of the folding blade cylindershown in FIG. 1, all three folding blades 18 are in the retractedinactive position. In this second, retracted position, it is possible torelease a fixed coupling, which is not specifically shown, between theoutboard flanges 13 and the inboard flanges 02 and thus to displace thefolding blades 18 in relation to the cradle 03 in a counterclockwisedirection in FIG. 1, so that each of the folding blades 18 comes to restin front of a gap 08, 09. The control cam 23, which is responsible forcontrolling the folding movement of the folding blades 18, is notrotated along in the course of this movement of the flanges 13 and 02with respect to each other, so that even after the displacement of theflanges the location at which the folding blades 18 are extended remainsat the place where the circumference of the folding blade cylindertouches the folding jaw cylinder, which folding jaw cylinder is notspecifically represented.

In the embodiment of the folding blade cylinder represented in FIG. 1,the two flanges 13 are connected with each other by L-shaped profiledelements 26 which, on their legs facing the inner surface 24 of thecradle 03, support a closing body 27 which is pressed against the innersurface 24 of the cradle 03 by a spring element 28. In this case, thespring element 28 and the closing body 27 are configured in one piece asa spring plate which is extending in the axial direction of the foldingblade cylinder over the entire length of the gaps 09. The closing bodies27 are arranged in relation to the folding blades in such a way thatthey close the gaps 09 when the folding blades 18 are aligned with thegaps 08, as represented in FIG. 1. These closing bodies 27 prevent afree end of a sheet that is being folded by the folding blades 18 fromspringing into the gap 09 and from getting snagged there. This isparticularly useful if the gap 08 corresponds to a delta foldingposition, which corresponds to a second transverse fold, and the gap 09corresponds to a first transverse folding position.

When the folding blades 18 are aligned with the gaps 09, the closingbodies 27 have retracted into the interior of the folding bladecylinder. Such a retracted closing body 27 is represented by adash-dotted line in FIG. 1 and is identified as 28′. On their interiorsurfaces, the gaps 09 each have beveled interior flanks 29 which, asseen more clearly in FIG. 3, and together with the curved exterior shapeof the closing body 27, make it easier for the dosing body 27 to retractinto the interior of the folding blade cylinder in the course of adisplacement of flanges 13 with respect to flanges 02.

Similar exterior beveled surfaces 31 are formed on each of the outeredges of each of the gaps 08, 09, again as seen most clearly in FIG. 3in order to prevent these outer edges from leaving pressure indentationson the sheets to be processed by the folding blade cylinder.

FIG. 3 shows a partial cross-section through a further embodiment of afolding blade cylinder in accordance with the present invention. Thedifference between this embodiment and the embodiment shown in FIG. 1lies in that in the embodiment shown in FIG. 3 the narrow cradle element07, under which the folding blade can move from the gap 08 to the gap 09and back, is thinner than the wide segments 06 on each of which thegrippers, which are not represented in FIG. 3, are arranged. FIG. 3shows the folding blade 18 in its retracted, inactive position. The tipof the folding blade 18 is located radially outward of the innersurfaces 32 of the thicker segments 06, but radially inside of the innersurfaces 33 of the thinner segments 07. In this way, the reducedthickness of the segment 07 permits the reduction of the lift of thefolding movement of the folding blade 18, but still allows it todisplace it as needed between the two gaps 08, 09. Along with thereduced lift of the folding movement, the accelerations to which thefolding blade, or its spindle 17, are subjected are also reduced. Thisallows for the operation of the folding blade cylinders at a greaterrotary speed and/or with reduced wear.

A second further embodiment of a folding blade cylinder in accordancewith the present invention is represented in FIG. 4 in a cross-sectionalview which is analogous to the one shown in FIG. 3. In the secondfurther embodiment the thickness of the cradle segments 06, 07 is againthe same, as in the case in the embodiment shown in FIG. 1. However, thecontrol cam 23 is now shaped in such a way that only a lift of thefolding movement, which lift is reduced in comparison with theembodiment in FIG. 1, is achieved. Thus, in the inactive, retractedposition of the lifting movement, which is not depicted in FIG. 4, thetip of the folding blade 18 is located radially between the cradle innersurface 24 and the outer surface of the cradle 03. In order to makepossible a displacement of the folding blades 18 between the two gaps08, 09 in spite of this inactive or retracted position of the foldingblade tip, linear actuators, which are in this case configured ashydraulic cylinders 34, are provided. The number of these linearactuators corresponds to the number of folding blades 18 and theselinear actuators are arranged distributed at the same angular distance.One of these hydraulic cylinders 34 is represented in FIG. 4. It ismounted on the flange 13, which also supports the folding blades 18, sothat it always remains in the same position with respect to the foldingblade 18 assigned to it, and independently of the rotary position of thefolding blade cylinder. The linear actuator, configured as a hydrauliccylinder 34, has an outwardly oriented piston with a piston rod 36,which piston rod 36 is located exactly opposite an end area of the lever21, or of the roller 22 mounted on the lever 21, which roller 22 ismounted for rolling off on the control cam 23. By extending the piston,and thus the piston rod 36, the roller 22 is lifted off the control cam23, and the folding blade 18 moves radially inwardly back past theinactive position represented in FIG. 4 and into the interior of thefolding blade cylinder. As described in connection with FIGS. 1 and 2,the flanges 13, 02 can be rotated in respect to each other in thisposition of the folding blades 18 in order to displace the foldingblades 18 out of their position at the gap 08 into the one at the gap09, or vice versa.

It would also be possible to mount the linear actuators fixed in place,in particular mounted on the control cam 23, and to provide the pistonrod 36 on its distal end with a cam section facing the roller 22, whichcam section would be at least sufficiently long for the roller 22 to beable to roll off on it in the course of the displacement of the foldingblade 18 from the gap 08 to the gap 09 or vice versa. In this way thefolding blade 18 would be maintained at a safe distance from the innersurface 24 of the cradle 03 during the entire displacement movement ofthe folding blades 18. Typically, this distance can be approximately 1.5mm.

The hydraulic cylinder 34 can be replaced by other types of linearactuators. For example, linear actuators with an electromagnetic drivemechanism could be utilized.

FIG. 5 shows a partial cross-section of a folding blade cylinder inaccordance with a third further embodiment of a folding blade cylinderin a plan view analogous to the views shown in FIGS. 3 and 4. Thestructure of the rotating elements of the folding blade cylinder are thesame as with the previously discussed embodiments and will not bedescribed again. In this third further embodiment, the folding blade 18is shown in its retracted position in its folding movement, shortlyprior to the roller 22 reaching a depression 37 in the control cam 23,which will cause the folding blade 18 to extend into its activeposition.

The roller 22 is wider than the control cam 23.

A second control cam 38 is represented as a dashed outline in FIG. 5.During normal operation of the folding blade cylinder, this secondcontrol cam 38 is spaced apart from the first control cam 23sufficiently far so that the roller 22 cannot touch it.

The second control cam 38 has areas 39, 41 of two different radii,wherein the radius of the smaller radius area 41 is slightly less thanthe radius of the control cam 34 in its area corresponding to theinactive state of the folding blade 18, while the radius of the largerradius area 39 of the second control cam 38 is clearly greater than thisvalue.

To perform the displacement of the folding blades 18, the second controlcam 38, which is initially situated in its orientation represented inFIG. 5, is axially displaced in the direction of the first control cam23, so that at least a portion of its width comes to lie underneath theroller 22. Thereafter, the second control cam 38 is turned in aclockwise direction, as depicted in FIG. 5. This causes the roller 22 tobe supported by the larger radius area 39 of the second control cam 38.The roller 22 is thus lifted off the first control cam 23, and thefolding blade 18 is retracted radially inwardly sufficiently far beyondits inactive position represented in FIG. 5 into the interior of thefolding blade cylinder so that the tip of the folding blade 18 clearlylies inside the inner surface 24 of the cradle 03. In this state, thedisplacement of the folding blade 18 can be performed in the same way asin the previously described embodiments. Thereafter, the second controlcam 38 is again moved away from the first control cam 23, so that thelatter can again take up its function of controlling the foldingmovement of the folding blade 18.

The embodiments shown and discussed are based on folding blade cylinderswith three folding blades, which three folding blades can be displacedbetween respectively two gaps. The invention can also be used inconnection with folding blade cylinders with any arbitrary number offolding blades and more than two gaps.

In the above described and depicted embodiments, a closing body 27 isonly provided for the gaps 09. A corresponding closing body could alsobe arranged on the opposite side of the folding blade 18 in order toclose the gap 08 when the folding blade 18 is positioned at the gap 09.

The folding blade 18 can be displaced between a working position, inwhich the folding blade 18 is arranged at least at times outside of acradle 03, and a position of rest, in which the folding blade 18 isarranged inside the cradle 03. In the process, the tip of the foldingblade 18 can be displaced, in a circumferential direction in relation tothe cradle 03, inside the cradle 03 so that it is moved along underneathsegments 07 of the cradle 03.

While preferred embodiments of a folding blade cylinder of a foldingblade machine in accordance with the present invention are set forthfully and completely hereinabove, it will be apparent to one of skill inthe art that various changes in, for example, the overall sizes of thecylinders, the drives for the cylinders, the sizes of the sheets beingfolded and the like could be made without departing from the true spiritand scope of the present invention which is accordingly to be limitedonly by the following claims.

1. A folding blade cylinder of a folding apparatus comprising: acylindrical cradle; at least first and second of axially extending,circumferentially spaced gaps in said cylindrical cradle; a foldingblade within said cylindrical cradle, said folding blade beingselectively extendable through a selected one of said at least first andsecond circumferentially spaced cradle gaps; and means forcircumferentially displacing said folding blade, while said foldingblade is in a rest position in an interior of the folding blade cylinderbetween selected at least first and second folding blade positions eachof which selected at least first and second folding blade positions islocated opposite a selected one of said at least first and secondcircumferentially spaced cradle gaps.
 2. The folding blade cylinder ofclaim 1 wherein said cradle includes cradle segments including thincradle segments and wherein said folding blade is displaceable beneathone of said thin cradle segments.
 3. The folding blade cylinder of claim1 further including a first folding blade control cam and a foldingblade lever, said lever riding on said first folding blade control camand controlling extension of said folding blades through said selectedones of said cradle gaps.
 4. The folding blade cylinder of claim 3further including an actuator adapted to lift said folding blade leveroff said first folding blade control cam.
 5. The folding blade cylinderof claim 4 wherein said actuator is a linear actuator selected from agroup including a working cylinder and an electromagnetic actuator. 6.The folding blade cylinder of claim 4 including a second control camthat is rotatable with respect to said first control cam, said secondcontrol cam being said actuator.
 7. The folding blade cylinder of claim1 further including a folding blade spindle supporting said foldingblade, said folding blade spindle being fixed in place in the foldingblade cylinder with respect to said cradle gaps during extension of saidfolding blade.
 8. The folding blade cylinder of claim 1 furtherincluding a folding jaw cylinder opposing the folding blade cylinder. 9.The folding blade cylinder of claim 1 wherein said folding blade ismovable between an extended active position and a retracted inactiveposition and further wherein said cradle has an inner surface, saidfolding blade in said retracted inactive position being located radiallyinteriorly of said cradle inner surface.
 10. The folding blade cylinderof claim 9 wherein said cradle includes cradle segments including thincradle segments and wherein said folding blade can be displaced behindone of said thin cradle segments.
 11. The folding blade cylinder ofclaim 1 further including beveled outer edges on said cradle gaps. 12.The folding blade cylinder of claim 1 further including a gap closingbody associated with ones of said cradle gaps not associated with saidfolding blade.
 13. The folding blade cylinder of claim 12 wherein saidgap closing body is displaceable with said folding blade.
 14. Thefolding blade cylinder of claim 13 wherein said cylinder gaps closableby said gap closing body have bevels on gap sides facing each other. 15.The folding blade cylinder of claim 14 further including a springelement, said spring element exerting a radially outwardly directedforce on said gap closing body.
 16. The folding blade cylinder of claim15 wherein said spring element and said gap closing body are one pieceof sheet metal strip.
 17. The folding blade cylinder of claim 13 furtherincluding a spring element, said spring element exerting a radiallyoutwardly directed force on said gap closing body.
 18. The folding bladecylinder of claim 17 wherein said spring element and said gap closingbody are one piece of sheet metal strip.